The present invention concerns a vehicle component according to the preamble of claim 1 and an external cover for this.
It is known to equip the floor panel of a vehicle with an acoustically active i.e. sound-insulating and/or sound-absorbing interior lining. Usually such a lining has a sound-insulating damping layer which is laid or glued directly onto the floor plate. In vehicles of higher comfort, on this vibration-damping and sound-insulating layer is applied a further sound-absorbing foam or fibre fleece layer and a heavy airtight carpet layer. These additional layers are matched to each other acoustically so that they can interact with each other as an acoustic spring-mass system. It is also known to apply a protective coating to the outside of the floor panel. This protective coating protects the floor panel mechanically and/or chemically for example against stone chips or road salt. Naturally this protective coating, referred to below as the underfloor coating, also contributes to additional damping of the vibrations of the floor panel.
As underfloor protect-on usually a relatively expensive PVC coating of approximately 1 mm thickness is sprayed on. Such a layer leads to a weight increase of around 1-1.5 kg/m2 and undesirably releases large quantities of chlorine on recycling.
It has been found that the multiplicity of layers and coatings of different functions applied to the floor plate undesirably increase the total weight of the vehicle and undesirably reduce the passenger space, in particular the foot space. The general aim of the modern vehicle industry however is to make vehicles lighter, more spacious and more economic.
It is therefore the task of the present invention to create a vehicle component which allows the foot space of the vehicle to be structured more spaciously without loss of acoustic effectiveness.
In addition a vehicle component is created which in comparison with conventional vehicle floor configurations is lighter and more cost effective and in particular raises no special disposal problems.
This task is solved according to the invention with the vehicle component according to claim 1 and an outer covering according to claim 13, and in particular in that on the outside of the body part is applied a strengthening shield at a distance from the said part which together with the body part forms a double floor structure. This double floor structure has a sound-insulating effect and can be combined with further sound-insulating and/or sound-absorbing elements.
In a preferred development of the vehicle component according to the invention a foam layer, in particular a soft foam, is introduced in the cavity of the double floor where the foam, preferably on its side facing the body part, is fitted with a profile. Such profiled dissipatively acting layers are known for example from EP 0 474 593 (which is hereby included in full scope as a constituent of this application) and rest loosely against the body part and damp the body vibrations. For this the soft foam and double floor are dimensioned such that the profiled soft foam is pressed against the body part by the shield of the double floor.
In a further preferred design of the vehicle component according to the invention the double floor is combined with an ultralight absorption package of the known type (for example according to WO98/18657, the content of which forms part of this application). Instead of a heavy layer this has a microporous stiffening layer. In this embodiment both the sound-insulating bituminous damping layer inside the vehicle and the heavy layer of the spring-mass system of the interior lining can be omitted.
This creates an acoustically active vehicle component which is considerably lighter than conventional systems and in the interior of the vehicle has a lower thickness. It is evident that by suitable combination of the double floor according to the invention with sound-insulating and/or sound-absorbing systems,of the known type, the acoustic efficacy can be improved further.
Preferred developments are defined by the features of the sub-claims.
The invention is now explained in more detail below with reference to design examples and the figures. Here: